A device of this type is known from DE 197 37 697 A1. The prior device comprises a casting mold in the form of an injection mold, in which a plastic blank, a so-called preform, is manufactured. In the blow mold this preform is blown to form the finished container. There are provided a plurality of casting molds, which are disposed on preferably two injection mold rotors, which move past an extruder one after the other, which fills the injection molds with liquid plastic. Next, the preforms formed in the injection molds are transferred to a transfer rotor, The transfer rotor then transfers the preforms to a blow molding rotor, which is provided with a plurality of circumferential blow molds. Each preform is inserted into a blow mold and blown to form the finished container.
The blowing is preferably accomplished by means of a stretching rod, which stretches the preform in an axial direction, while the introduced compressed gas (usually air) entails a radial stretching of the preform. Stretching rods are commonly used for the manufacture of plastic containers and are described, for instance, in U.S. Pat. No. 4,039,641.
One problem involved by the transfer of the injection molded preform to the blow mold is the temperature control, which is never exactly definable because the preforms, when being transferred, are exposed to exterior conditions that vary according to the ambient conditions (outside temperature). Therefore, it is safer to let the preforms cool down and provide a heater for heating the preforms to a predetermined temperature for the blowing process. In addition, the prior device is very complex with regard to its construction and requires plenty of floor space.